  |
はてなキーワード: FUELとは
健康の為、天気の良い日は片道15kmほどの通勤を自転車（クロスバイク）にしている
どうせならと思い、ポケモンGOの為に装備を整えた
スマホを操作する際には、前後を良く確認して車の邪魔にならないよう停車して操作しなければならない
結果的にポケモンを捕まえる為、30分ほど早く家を出る事になってしまった
万が一があってはならないので、多少値は張るが安心できるものを選んだ
トピーク（TOPEAK） ライドケース iPhone 6 PLUS用 セット http://amazon.jp/dp/B00S0PJ9IQ
￥ 4,752
当然、運転中に常に画面を見ているわけにはいかない
DIGICare 骨伝導ヘッドホン ワイヤレスBluetooth (ブラック) http://amazon.jp/dp/B01DQEAT3E
￥ 6,280
モバイルバッテリーをマウントする為に、トップチューブバッグを購入した
TOPEAK【トピーク】 Fuel Tank【フュエルタンク】 トップチューブバッグ http://amazon.jp/dp/B00UV65UVM
￥ 4,148
計￥15,180-
なるほど、スマホゲーは高くつくんだな
理系はてなーのみなさんは、MIRAIに関するさまざまな問題点の指摘をすでに目にしているだろう。
曰く、水素自動車に使われる水素は結局は電気で作るほかなく、その電気は化石燃料含めた既存の発電設備で作る。化石燃料をそのまま使う内燃機関車や、電気の段階でエネルギーを受け渡すEVより多段階のエネルギー変換をしているわけだから、そのぶんエネルギー効率が落ちている（実際、コストで比較するとHVやEVよりも燃費は悪い）。水素ステーションという社会的インフラ基盤を整備するコストも高い。液体ではなく気体を扱うわけだから設備にもそれだけ高い保安性能が要求される。1拠点で1億円かかると言われている。エネルギーロスがある技術に、多大な社会的投資が必要になる。
これらはすべて、MIRAIという車両の「川上」に属する問題だ。でも、MIRAI自体の問題について指摘した文章をあまり目にしていない。そこにこそ「MIRAI（FCV）には未来がない」ことの雄弁な証拠があるというのに。
なんでMIRAIには未来はないと思うのか。端的に、でかすぎ、重すぎなのだ。クラウンよりも5mm短くて横幅が15mmでかい。同サイズ以上。車重は2000kgオーバー。定員は4名で、後部座席の足元は前席下に入らない。トランクは狭小。これが、FCVに未来がないことの証拠だ。
そんなことがなぜ問題なのか。「初代の実験的販売車だからいいじゃないか。そのうち改善されていくだろう」。そうではない。たとえば初代プリウスはMIRAIより全長が600mm、横幅は100mm短く、車重は1200kg台で、定員5名だった。MIRAIより800kgも軽いのだ！ 初代プリウスをあれだけコンパクトなパッケージにまとめたトヨタが、MIRAIでは会社の命運を賭けてもここまでのパッケージングしかできなかったということが、FCVの将来を暗示している。MIRAIはHVに比べても、積載している技術要素が多く、しかもそれぞれ小型軽量化するのが困難な技術的制約があるから、この大きさと重さになってしまっている。以下、それぞれの技術要素について言及する。
まずFCスタック、燃料電池部が重くてでかい。この重さと大きさでどうにか155psを確保した。2tを超える車重を動かすにはおっつかっつのレベルだ。しかも、その性能（重量出力比）を規定しているのが化学反応の領域なので、技術革新のペースが電子技術や機械技術よりも格段に遅い。これは燃料電池だけでなく、電池技術の一般的な命題として知られている。実用車として必要な出力を確保するには、大幅な小型化は難しいだろう。
高圧水素タンクも重くてでかい。でも、これ以上小さくすると650kmという内燃エンジン車の平均的航続距離を切ってしまう。タンク圧を上げればそれだけリスクが増す。現状でも水素自動車スタンドでは危険性を考慮し、専任オペレータがチャージしなければならない（＝セルフ補充はできない）仕様なのだから、これ以上の高圧化の可能性はないだろう。そしてタンクの耐用年数は15年だ。しかも2年毎に定期点検が必要になり、一般の車検場では検査はできない。とてもエコだのサステナビリティだのを胸を張って主張できるような代物ではない。
水素ガスの供給系も重いしでかい。燃焼性の液体を発火プラグの直前で気化する内燃機関に比べて、気体を高圧タンクからスタックまで送り込むのだから、配管の気密性もポンプの性能も桁違いに保安基準が高く、それだけ重く大きくなる。これも技術的制約であり、簡単に解決できるようなものではない。ちなみにこの車には数ヵ所に水素ガスのガス漏れ検知装置がついている。
廃熱系も重くてでかい。水素自動車は水しか排出しない。つまり排ガス経由で廃熱を抜けない。しかし燃料電池部分はかなりの発熱を伴う。FCスタックで起きているのは、酸素と水素から電気と水と熱を作る反応だからだ。だからあの異形の巨大グリルが必要になり、その内部に大型のラジエーターが鎮座している。これも化学反応の特性に紐付けられた制約だから、技術革新で容易に克服できるものではない。
バッテリも、EVほどではないにしろ、それなりに重くてでかい。FCスタックだけでは柔軟な出力制御や回生はできない。だから大型の補助バッテリセルを積んでいる。FCスタック+モーター+バッテリというパワートレイン。これエンジン+モーター+バッテリとパラレルな、要はHV車と同じような構成なのだ。HV並みにパワートレインの構成が複雑で、構成部品も多い。しかも可燃性気体を扱うぶんだけ重く大きくなる。これは技術革新だけでどうにかできるような問題ではない。FCVという特定のテクノロジーの組み合わせによる、固有の限界、固有の制約というものがある。それがMIRAIの初期モデルの性能と価格を規定している。こう説明すれば、理系はてなーは直感的に「あっこれ、技術的に筋が悪いな」と感じるのではないだろうか。
だから値段も高い。補助金なしなら700万円オーバーだ。そこに、国民の皆様の血税が220万円注ぎ込まれて、やっと500万円程度になる。ちなみに初代プリウスは補助金なしで215万円だった。おわかりいただけただろうか。だからMIRAIには未来がないのだ。
2021年6月16日、ホンダ・クラリティFuel Cellの生産中止が発表された。ホンダ、FCV生産中止 販売低調で : 日本経済新聞 理由は販売低調。そりゃそうだ、高い（783万円）、でかい（全長4915mm・全幅1875mm）、買いにくい（リース専用）。2021年6月時点でも全国の水素ステーションの数は147箇所止まり。助成金たんまり乗せて官公庁と法人に買ってもらうしかマーケットがない。そもそもクルマとしてのユーティリティが乏しいFCVで、さらにあえてホンダ車を選ばなければならない自治体や企業はほとんどない。全世界での累計販売台数はわずか1900台だったそうだ。FCV全体を断念するわけではなくGM合弁でFCVは続けるということだが、あくまで保険的なムーブだろう。
もう一方のトヨタ・MIRAIはどうなったかといえば、こちらも累計販売1万台・国内販売3700台と全く振るわない状況だったが、2020年12月にガラッと雰囲気の変わった2代目が出てきた。https://toyota.jp/mirai これが実にお見事なのだ。といっても「これなら売れる！ FCVの時代が来た！」という意味ではない。5年前にこの増田で書いた諸問題をまったく解決できないまま、それでも「FCVには将来性がある」という幻想を維持するために、針の穴に糸を通すようなコントロールで商品企画をやり直し、それにある程度成功している、ということだ。
どういうことか。まずボディサイズだ。レクサスLSと同じGA-Lプラットフォームを採用して、全長4975mm・全幅1885mmに。ちなみに初代は全長4890mm・全幅1815mmだった。初代よりひとまわりデカくなっているのである！ 価格は？ 細かくグレードを刻んで710万円〜860万円。こちらも高くなっている！ 高圧タンクはどうなった？ なんと3本に増槽している。しかも1本は運転席の真横に据え付けられている。
全幅1885mmにして、巨大なフロアトンネルにも水素タンクを入れて、750〜850kmという航続距離を確保。全長4975mmにして、ゴルフバッグ3個分のトランクを確保。大径タイヤを採用して地上高を上げ、タンク寸法を拡大。とにかく、全体をデカくすることでどうにかした。「技術的課題を解決しないという解決をした」ともいえる。
一方でトヨタはさすがだなと思うのは、そういう「FCVの限界に気づかせないための、ほぼ唯一の正解ルート」を新型MIRAIでちゃんと選んでることだ。上司に「お前、FCVなんとかしろや」と言われた時に現場が練ってくる商品企画としては、ほぼ100点満点といえる。つまり、デカさと高さを「これはあくまで高級車、ラグジュアリーカーなんですよ〜」という建て付けにすることで、「要素技術的に小型化・低価格化が困難」という自家用FCVの致命的欠点を希釈したのである。
自家用FCVの「デカい・狭い・高い問題」を誤魔化せるのは、もともとボディサイズが大きいスポーツ寄りの大型セダンか大型SUVぐらいしかない。だがエコカーの上得意である自治体や法人はSUVを買わない。だからMIRAIは「レクサスLSみたいな、スポーツ寄りの大型セダン」になった。2代目MIRAIは、顔つきこそスポーツカーっぽいが、シルエット的にはギリギリ自治体・法人用のショーファードリブンカーにも富裕層向けのドライバーズサルーンにも見えるし、実際に両方のニーズをそこそこ満たせるように作ってある。辻褄は合ってる。
ショーファードリブン用途に供するために、狭い車内で後部左右席をめいっぱい広く取った。だから後部中央席は実用に向かない。あくまで「5人定員」というカタログスペックのためのエマージェンシーシートだ。これはファミリーカーなら大きな欠点だが、ショーファードリブンやドライバーズサルーンなら別に困らない。ほとんど使わないから。辻褄は合ってる。
後部中央席を実際に使わない想定なら、フロアトンネルを大きくしてそこに水素タンクを増槽してもいいよね、となる。結果として航続距離が伸び、600km→850kmになった。これで水素ステーション不足の問題をある程度緩和できている。辻褄は合ってる。
ガッチガチの制約条件の中で唯一の正答を導く論理パズルみたいなことになってて、しかもちゃんと正解してる。さすがトヨタ。だがこれは「やっぱりFCVで大衆乗用車（5人乗り＋5ナンバー）を作るのは無理でした」という事実上の敗北宣言でもある。やはりMIRAIには未来がないのだ。
おそらくトヨタも、自家用FCVという路線にはもう勝ち目が薄いと認識していると思う。そこで繰り出してきたのが水素エンジンという隠し球。技術的にはそう目新しくなく、過去にも複数メーカーが販売している。ただカーボンオフセットが問題視される以前は既存のガソリン内燃車に比べて全く優位性がなかったし、そもそも世の中に水素燃料のサプライチェーンが存在していないから普及することもなかった。
でもFCV普及が厳しくなった今、水素エンジン車は、既存自動車メーカーが手持ちの技術資源を使ってEV勢に対抗しうる希少な選択肢になる。内燃で培った基幹技術の多くを使い回せるので、今からでもイノベーションで先行するEV勢にキャッチアップしやすい。ミッション系ほか大手下請サプライヤーもそのまま連れて行ける。ガソリンに比べて重量エネルギー効率はかなり悪いが、お得意のHV機構と絡めれば何とか燃費も実用域まで持っていける可能性はある。官民を巻き込んだ水素ステーション全国展開というプロジェクトの延命もできる。モジュール化に不向きなので中長期ではEV勢に対してどうしても不利になっていくが、レガシーの技術を延命させて戦えるとこまで戦うというのも旧主派勢力の立派な戦略だ。3代目MIRAIは、出るとしたら普通の水素エンジンHV車に生まれ変わっているかもしれない。
（続きを書きました https://anond.hatelabo.jp/20210820195856
このタイトルを見てFuelPHP(以下、Fuel)が勝ちだとか、Rubyのほうが優れてるだとか、思った方はいますぐ反省するべき。
FuelはRESTfulなアクセスやセッションのサポートしているなど、フレームワーク自体が最近のウェブサービス思考に対応し、また、ローカルの開発の場合はSQLite(もつかえる)を使うなど、開発環境においても最近の流行を取り入れています。gitとの相性も良いです。
Fuelの最大の魅力はComposerと呼ばれるphpのライブラリパッケージシステムでしょう。Fuel(のコア)自体もComposerの1つで、Composerを使わないFuelアプリケーションはありません。（というかComposerを使わないのであればFuelである必要がない。）
フレームワークを拡張するプラグインが幾つもあることにより、Fuelは汎用性が高くも多くの人に使われるフレームワークであるといえます。
http://anond.hatelabo.jp/20140908171411
http://anond.hatelabo.jp/20140909093834
に便乗してみます。
はじめに
35歳男性、週に多いときで3～4日、1～2時間程度、少ないときは数週間以上ゲームしない。
便宜上、嫌いなゲームを書いてますが正確には途中でプレイをやめたゲームです。
①箱庭ゲーム
好きなゲーム
・JustCause2
・Far Cry3
→一人称視点しかないのが最初辛かったけど意外と慣れた。スナイパー無双なプレイ
嫌いなゲーム
・GTA5
→最初のチュートリアル終って自由に動ける段階で何していいか迷って結果飽きてしまう。
②箱庭レース
好きなゲーム
・FUEL
→レースは最悪だけどそれを補って余りあるほど自由に走れるから好き。繰り返すと、レースはひたすらムカつく。
・Burnout Paradise
→街中の隠し通路やジャンプポイントを探すのが楽しい。レースもただ速さだけでなく相手をクラッシュさせたりして楽しい
・NEED FOR SPEED MOST WANTED
→Burnout Paradiseと同じく街中の隠し通路やジャンプポイントを探すのが楽しい。警察との追いかけっこもよい。
嫌いなゲーム
→チュートリアル終って次のミッションができない。それよりも街中を走っても楽しさを感じない。
・Need For Speed Rivals
The green environmental protection battery is to point to in recent years has been put into use or are development, the development of kind of high performance, no pollution batteries. At present already use large nickel metal hydride battery, the lithium ion battery and is expanded use of mercury free alkaline battery manganese zinc and rechargeable batteries and is research and development of lithium or lithium ion plastic pack and fuel cells belong to this category. In addition, it is widely used and use of solar energy for photoelectric convert solar cell (also called photovoltaic power generation), can also be included in this category.
Nickel metal hydride battery (Ni-MH) and nickel cadmium battery (Ni-Cd) have the same working voltage (1.2 V), due to the adoption of rare earth alloy or TiNi alloy anode materials for the activity of hydrogen storage material, replacing the carcinogen cadmium, which not only makes this battery became a kind of green environmental protection battery, and make a battery of energy than increased nearly 40%, to 80-60 Wh/kg and 210-240 Wh/L. The battery is 90 s gradually realize industrialization PANASONIC VW-VBK360 Battery , and the first to use in the cell phone battery. At present although it on their dominance of the gradually be lithium ion battery replaced, but mobile phone applications in Europe and America, and its market share is still at about 50%.
The lithium ion battery (Li-ion) is by can make the lithium ion embedding and take off the carbon embedded as negative, reversible intercalated-li metal oxide as the positive (LiCoO2, LiNiO2 or LiMn2O4) and organic electrolyte constitute, the working voltage of 3.6 V, so a lithium-ion battery is equivalent to three cadmium nickel metal hydride battery or nickel. Thus the batteries than energy is the over 100 Wh/kg and 280 Wh/L, and considerably more than the nickel metal hydride battery than energy. In view of the above advantages, since the 1993-2000 in just a few years, its production and usage with extremely high speed growth.
Alkaline manganese zinc dry (alkaline) compared with ordinary dry cell size has higher capacity PANASONIC CGA-S005E Battery, and have high discharge current ability. In recent years has been used on mercury zinc powder, therefore make the battery become a green battery, and become the mainstream battery products, at present the alkaline xinmeng dry cell is still BP machine use most power supply. At the same time, the world is the battery charged on the sex, an American company has launched a charged battery alkali manganese, product and application of slow growth. Such batteries keep the battery discharge characteristics, but also can be recharged using a dozen times to hundreds of times (deep recharge cycles life of about 25 times).
Lithium plastic battery (LIP) is for lithium metal anode, conductive polymers of electrolyte for new battery, the energy than has reached 170 Wh/kg and 350 Wh/L. The lithium ion battery is will present plastic of organic lithium ion battery electrolyte stored in a polymer membrane, or use conductive polymer as electrolyte, make a battery in no free the electrolyte. Such batteries can use aluminum plastic composite membrane realize hot pressing encapsulation, with light weight, shape can be arbitrary change, safety better characteristics.
Fuel cells (FC) is a kind of use of fuel (such as hydrogen or contain fuel) and antioxidant (such as pure oxygen or the oxygen in air) for power generation device directly, because avoided the carnot cycle limit, this power unit is not only high efficiency (electrochemical reactions conversion efficiency can be as high as 40% or more), and no pollution discharge gas, so is the future of efficient and clean power generation method. Many companies at home and abroad are engaged in development for mobile phones, notebook computers, the PEM fuel cell, once put into application, and its economy benefit greatly.
Seal lead-acid battery is a kind of lead-acid batteries.
The following new green battery technology and related industry development is rapid.
1. Hydrogen storage material and nickel metal hydride Battery-the nimh batteries (PANASONIC CGA-S101E/1B Battery)
2. Lithium ion embedded material and liquid electrolyte of lithium ion battery
3. Polymer electrolyte of lithium battery or lithium ion battery
4. Zinc air battery and PEM fuel cell
In addition to the above, in view of the communication industry growth, China's battery industry is with extremely high speed to promote environmental protection mercury-free alkali manganese zinc original pool and rechargeable batteries and seal lead-acid battery technology development and application expansion market.
Apple on an application for a patent for the fuel cells on Thursday are exposed. In the patent application, apple describes a kind of electronic equipment, such as notebook computer use fuel cells, and without any increase in too much weight of fuel cell performance optimization method.
An application for a patent for the title as "for portable computing devices power supply of fuel cell system". Apple says, consumers are becoming more and more attention to use of renewable energy. Fuel cell in technology competitive, as the energy density high, compared with the traditional batteries can be in the same volume provide more energy.
Apple patent application show: "fuel cells and additional fuel can bring high energy density, in not adding fuel to support of portable electronic devices for days or even weeks." Apple also said, use a fuel cell is to face the challenge of portability and cost.
Usually, the fuel cells to electronic equipment support portable charging, and users need to carry a fuel rods. And this is different, have conceived a and apple electronic equipment tightly integrated fuel cell. And this one the bulk of the patent application in a description of a fuel cell stack is used to optimize the flow of energy control system.
Another apple patent application describes how the fuel cell and rechargeable batteries work together, and to make the fuel cell and rechargeable batteries charging each other. This patent application said: "it will be to make the fuel cell system not necessary to large and heavy integration of the battery, thus obviously reduce the fuel cell system size, weight and cost."
This is not the first application for apple about fuel cell patent. Patently Apple web site said, October the exposure to a patent application shows that Apple are designing a fuel panels, from portable equipment to produce more energy.
About fuel itself, apple a patent application shows that there are a variety of fuel for power electronic equipment, one of which is sodium borohydride and water mixture. But these are still at the experimental stage, has yet to commercial.
Portable fuel cell charger faces a major obstacle is that manufacturers need to establish sales channel sales and recycled fuel rods. Apple will likely use apple retail stores to have finished the work.
____________
http://www.chargerbatteryshop.co.uk/panasonic-lumix-dmc-fs62-battery-charger-cbbs.html
http://www.gobatteryonline.com/canon-powershot-a3000-is-battery-charger-gose.html
When the diesel generators were gone, the reactor operators switched to emergency battery power. The batteries were designed as one of the backups to the backups, to provide power for cooling the core for 8 hours. And they did.
Within the 8 hours, another power source had to be found and connected to the power plant. The power grid was down due to the earthquake. The diesel generators were destroyed by the tsunami. So mobile diesel generators were trucked in.
This is where things started to go seriously wrong. The external power generators could not be connected to the power plant (the plugs did not fit). So after the batteries ran out, the residual heat could not be carried away any more.
At this point the plant operators begin to follow emergency procedures that are in place for a “loss of cooling event”. It is again a step along the “Depth of Defense” lines. The power to the cooling systems should never have failed completely, but it did, so they “retreat” to the next line of defense. All of this, however shocking it seems to us, is part of the day-to-day training you go through as an operator, right through to managing a core meltdown.
It was at this stage that people started to talk about core meltdown. Because at the end of the day, if cooling cannot be restored, the core will eventually melt (after hours or days), and the last line of defense, the core catcher and third containment, would come into play.
But the goal at this stage was to manage the core while it was heating up, and ensure that the first containment (the Zircaloy tubes that contains the nuclear fuel), as well as the second containment (our pressure cooker) remain intact and operational for as long as possible, to give the engineers time to fix the cooling systems.
Because cooling the core is such a big deal, the reactor has a number of cooling systems, each in multiple versions (the reactor water cleanup system, the decay heat removal, the reactor core isolating cooling, the standby liquid cooling system, and the emergency core cooling system). Which one failed when or did not fail is not clear at this point in time.
So imagine our pressure cooker on the stove, heat on low, but on. The operators use whatever cooling system capacity they have to get rid of as much heat as possible, but the pressure starts building up. The priority now is to maintain integrity of the first containment (keep temperature of the fuel rods below 2200°C), as well as the second containment, the pressure cooker. In order to maintain integrity of the pressure cooker (the second containment), the pressure has to be released from time to time. Because the ability to do that in an emergency is so important, the reactor has 11 pressure release valves. The operators now started venting steam from time to time to control the pressure. The temperature at this stage was about 550°C.
This is when the reports about “radiation leakage” starting coming in. I believe I explained above why venting the steam is theoretically the same as releasing radiation into the environment, but why it was and is not dangerous. The radioactive nitrogen as well as the noble gases do not pose a threat to human health.
At some stage during this venting, the explosion occurred. The explosion took place outside of the third containment (our “last line of defense”), and the reactor building. Remember that the reactor building has no function in keeping the radioactivity contained. It is not entirely clear yet what has happened, but this is the likely scenario: The operators decided to vent the steam from the pressure vessel not directly into the environment, but into the space between the third containment and the reactor building (to give the radioactivity in the steam more time to subside). The problem is that at the high temperatures that the core had reached at this stage, water molecules can “disassociate” into oxygen and hydrogen – an explosive mixture. And it did explode, outside the third containment, damaging the reactor building around. It was that sort of explosion, but inside the pressure vessel (because it was badly designed and not managed properly by the operators) that lead to the explosion of Chernobyl. This was never a risk at Fukushima. The problem of hydrogen-oxygen formation is one of the biggies when you design a power plant (if you are not Soviet, that is), so the reactor is build and operated in a way it cannot happen inside the containment. It happened outside, which was not intended but a possible scenario and OK, because it did not pose a risk for the containment.
So the pressure was under control, as steam was vented. Now, if you keep boiling your pot, the problem is that the water level will keep falling and falling. The core is covered by several meters of water in order to allow for some time to pass (hours, days) before it gets exposed. Once the rods start to be exposed at the top, the exposed parts will reach the critical temperature of 2200 °C after about 45 minutes. This is when the first containment, the Zircaloy tube, would fail.
And this started to happen. The cooling could not be restored before there was some (very limited, but still) damage to the casing of some of the fuel. The nuclear material itself was still intact, but the surrounding Zircaloy shell had started melting. What happened now is that some of the byproducts of the uranium decay – radioactive Cesium and Iodine – started to mix with the steam. The big problem, uranium, was still under control, because the uranium oxide rods were good until 3000 °C. It is confirmed that a very small amount of Cesium and Iodine was measured in the steam that was released into the atmosphere.
It seems this was the “go signal” for a major plan B. The small amounts of Cesium that were measured told the operators that the first containment on one of the rods somewhere was about to give. The Plan A had been to restore one of the regular cooling systems to the core. Why that failed is unclear. One plausible explanation is that the tsunami also took away / polluted all the clean water needed for the regular cooling systems.
The water used in the cooling system is very clean, demineralized (like distilled) water. The reason to use pure water is the above mentioned activation by the neutrons from the Uranium: Pure water does not get activated much, so stays practically radioactive-free. Dirt or salt in the water will absorb the neutrons quicker, becoming more radioactive. This has no effect whatsoever on the core – it does not care what it is cooled by. But it makes life more difficult for the operators and mechanics when they have to deal with activated (i.e. slightly radioactive) water.
But Plan A had failed – cooling systems down or additional clean water unavailable – so Plan B came into effect. This is what it looks like happened:
In order to prevent a core meltdown, the operators started to use sea water to cool the core. I am not quite sure if they flooded our pressure cooker with it (the second containment), or if they flooded the third containment, immersing the pressure cooker. But that is not relevant for us.
The point is that the nuclear fuel has now been cooled down. Because the chain reaction has been stopped a long time ago, there is only very little residual heat being produced now. The large amount of cooling water that has been used is sufficient to take up that heat. Because it is a lot of water, the core does not produce sufficient heat any more to produce any significant pressure. Also, boric acid has been added to the seawater. Boric acid is “liquid control rod”. Whatever decay is still going on, the Boron will capture the neutrons and further speed up the cooling down of the core.
The plant came close to a core meltdown. Here is the worst-case scenario that was avoided: If the seawater could not have been used for treatment, the operators would have continued to vent the water steam to avoid pressure buildup. The third containment would then have been completely sealed to allow the core meltdown to happen without releasing radioactive material. After the meltdown, there would have been a waiting period for the intermediate radioactive materials to decay inside the reactor, and all radioactive particles to settle on a surface inside the containment. The cooling system would have been restored eventually, and the molten core cooled to a manageable temperature. The containment would have been cleaned up on the inside. Then a messy job of removing the molten core from the containment would have begun, packing the (now solid again) fuel bit by bit into transportation containers to be shipped to processing plants. Depending on the damage, the block of the plant would then either be repaired or dismantled.
Now, where does that leave us?
・The plant is safe now and will stay safe.
・Japan is looking at an INES Level 4 Accident: Nuclear accident with local consequences. That is bad for the company that owns the plant, but not for anyone else.
・Some radiation was released when the pressure vessel was vented. All radioactive isotopes from the activated steam have gone (decayed). A very small amount of Cesium was released, as well as Iodine. If you were sitting on top of the plants’ chimney when they were venting, you should probably give up smoking to return to your former life expectancy. The Cesium and Iodine isotopes were carried out to the sea and will never be seen again.
・There was some limited damage to the first containment. That means that some amounts of radioactive Cesium and Iodine will also be released into the cooling water, but no Uranium or other nasty stuff (the Uranium oxide does not “dissolve” in the water). There are facilities for treating the cooling water inside the third containment. The radioactive Cesium and Iodine will be removed there and eventually stored as radioactive waste in terminal storage.
・The seawater used as cooling water will be activated to some degree. Because the control rods are fully inserted, the Uranium chain reaction is not happening. That means the “main” nuclear reaction is not happening, thus not contributing to the activation. The intermediate radioactive materials (Cesium and Iodine) are also almost gone at this stage, because the Uranium decay was stopped a long time ago. This further reduces the activation. The bottom line is that there will be some low level of activation of the seawater, which will also be removed by the treatment facilities.
・The seawater will then be replaced over time with the “normal” cooling water
・The reactor core will then be dismantled and transported to a processing facility, just like during a regular fuel change.
・Fuel rods and the entire plant will be checked for potential damage. This will take about 4-5 years.
・The safety systems on all Japanese plants will be upgraded to withstand a 9.0 earthquake and tsunami (or worse)
・I believe the most significant problem will be a prolonged power shortage. About half of Japan’s nuclear reactors will probably have to be inspected, reducing the nation’s power generating capacity by 15%. This will probably be covered by running gas power plants that are usually only used for peak loads to cover some of the base load as well. That will increase your electricity bill, as well as lead to potential power shortages during peak demand, in Japan.
If you want to stay informed, please forget the usual media outlets and consult the following websites:
http://www.world-nuclear-news.org/RS_Battle_to_stabilise_earthquake_reactors_1203111.html
http://bravenewclimate.com/2011/03/12/japan-nuclear-earthquake/
http://ansnuclearcafe.org/2011/03/11/media-updates-on-nuclear-power-stations-in-japan/
結論：大丈夫。
MvK2010
I'm going to copy paste a full blog post of a research scientist at MIT here, who explains the situation at Fukushima much better than anyone else has, his message: no worries.
This post is by Dr Josef Oehmen, a research scientist at MIT, in Boston.
He is a PhD Scientist, whose father has extensive experience in Germany’s nuclear industry. I asked him to write this information to my family in Australia, who were being made sick with worry by the media reports coming from Japan. I am republishing it with his permission.
It is a few hours old, so if any information is out of date, blame me for the delay in getting it published.
This is his text in full and unedited. It is very long, so get comfy.
I am writing this text (Mar 12) to give you some peace of mind regarding some of the troubles in Japan, that is the safety of Japan’s nuclear reactors. Up front, the situation is serious, but under control. And this text is long! But you will know more about nuclear power plants after reading it than all journalists on this planet put together.
There was and will *not* be any significant release of radioactivity.
By “significant” I mean a level of radiation of more than what you would receive on – say – a long distance flight, or drinking a glass of beer that comes from certain areas with high levels of natural background radiation.
I have been reading every news release on the incident since the earthquake. There has not been one single (!) report that was accurate and free of errors (and part of that problem is also a weakness in the Japanese crisis communication). By “not free of errors” I do not refer to tendentious anti-nuclear journalism – that is quite normal these days. By “not free of errors” I mean blatant errors regarding physics and natural law, as well as gross misinterpretation of facts, due to an obvious lack of fundamental and basic understanding of the way nuclear reactors are build and operated. I have read a 3 page report on CNN where every single paragraph contained an error.
We will have to cover some fundamentals, before we get into what is going on.
Construction of the Fukushima nuclear power plants
The plants at Fukushima are so called Boiling Water Reactors, or BWR for short. Boiling Water Reactors are similar to a pressure cooker. The nuclear fuel heats water, the water boils and creates steam, the steam then drives turbines that create the electricity, and the steam is then cooled and condensed back to water, and the water send back to be heated by the nuclear fuel. The pressure cooker operates at about 250 °C.
The nuclear fuel is uranium oxide. Uranium oxide is a ceramic with a very high melting point of about 3000 °C. The fuel is manufactured in pellets (think little cylinders the size of Lego bricks). Those pieces are then put into a long tube made of Zircaloy with a melting point of 2200 °C, and sealed tight. The assembly is called a fuel rod. These fuel rods are then put together to form larger packages, and a number of these packages are then put into the reactor. All these packages together are referred to as “the core”.
The Zircaloy casing is the first containment. It separates the radioactive fuel from the rest of the world.
The core is then placed in the “pressure vessels”. That is the pressure cooker we talked about before. The pressure vessels is the second containment. This is one sturdy piece of a pot, designed to safely contain the core for temperatures several hundred °C. That covers the scenarios where cooling can be restored at some point.
The entire “hardware” of the nuclear reactor – the pressure vessel and all pipes, pumps, coolant (water) reserves, are then encased in the third containment. The third containment is a hermetically (air tight) sealed, very thick bubble of the strongest steel. The third containment is designed, built and tested for one single purpose: To contain, indefinitely, a complete core meltdown. For that purpose, a large and thick concrete basin is cast under the pressure vessel (the second containment), which is filled with graphite, all inside the third containment. This is the so-called “core catcher”. If the core melts and the pressure vessel bursts (and eventually melts), it will catch the molten fuel and everything else. It is built in such a way that the nuclear fuel will be spread out, so it can cool down.
This third containment is then surrounded by the reactor building. The reactor building is an outer shell that is supposed to keep the weather out, but nothing in. (this is the part that was damaged in the explosion, but more to that later).
Fundamentals of nuclear reactions
The uranium fuel generates heat by nuclear fission. Big uranium atoms are split into smaller atoms. That generates heat plus neutrons (one of the particles that forms an atom). When the neutron hits another uranium atom, that splits, generating more neutrons and so on. That is called the nuclear chain reaction.
Now, just packing a lot of fuel rods next to each other would quickly lead to overheating and after about 45 minutes to a melting of the fuel rods. It is worth mentioning at this point that the nuclear fuel in a reactor can *never* cause a nuclear explosion the type of a nuclear bomb. Building a nuclear bomb is actually quite difficult (ask Iran). In Chernobyl, the explosion was caused by excessive pressure buildup, hydrogen explosion and rupture of all containments, propelling molten core material into the environment (a “dirty bomb”). Why that did not and will not happen in Japan, further below.
In order to control the nuclear chain reaction, the reactor operators use so-called “moderator rods”. The moderator rods absorb the neutrons and kill the chain reaction instantaneously. A nuclear reactor is built in such a way, that when operating normally, you take out all the moderator rods. The coolant water then takes away the heat (and converts it into steam and electricity) at the same rate as the core produces it. And you have a lot of leeway around the standard operating point of 250°C.
The challenge is that after inserting the rods and stopping the chain reaction, the core still keeps producing heat. The uranium “stopped” the chain reaction. But a number of intermediate radioactive elements are created by the uranium during its fission process, most notably Cesium and Iodine isotopes, i.e. radioactive versions of these elements that will eventually split up into smaller atoms and not be radioactive anymore. Those elements keep decaying and producing heat. Because they are not regenerated any longer from the uranium (the uranium stopped decaying after the moderator rods were put in), they get less and less, and so the core cools down over a matter of days, until those intermediate radioactive elements are used up.
This residual heat is causing the headaches right now.
So the first “type” of radioactive material is the uranium in the fuel rods, plus the intermediate radioactive elements that the uranium splits into, also inside the fuel rod (Cesium and Iodine).
There is a second type of radioactive material created, outside the fuel rods. The big main difference up front: Those radioactive materials have a very short half-life, that means that they decay very fast and split into non-radioactive materials. By fast I mean seconds. So if these radioactive materials are released into the environment, yes, radioactivity was released, but no, it is not dangerous, at all. Why? By the time you spelled “R-A-D-I-O-N-U-C-L-I-D-E”, they will be harmless, because they will have split up into non radioactive elements. Those radioactive elements are N-16, the radioactive isotope (or version) of nitrogen (air). The others are noble gases such as Xenon. But where do they come from? When the uranium splits, it generates a neutron (see above). Most of these neutrons will hit other uranium atoms and keep the nuclear chain reaction going. But some will leave the fuel rod and hit the water molecules, or the air that is in the water. Then, a non-radioactive element can “capture” the neutron. It becomes radioactive. As described above, it will quickly (seconds) get rid again of the neutron to return to its former beautiful self.
This second “type” of radiation is very important when we talk about the radioactivity being released into the environment later on.
I will try to summarize the main facts. The earthquake that hit Japan was 7 times more powerful than the worst earthquake the nuclear power plant was built for (the Richter scale works logarithmically; the difference between the 8.2 that the plants were built for and the 8.9 that happened is 7 times, not 0.7). So the first hooray for Japanese engineering, everything held up.
When the earthquake hit with 8.9, the nuclear reactors all went into automatic shutdown. Within seconds after the earthquake started, the moderator rods had been inserted into the core and nuclear chain reaction of the uranium stopped. Now, the cooling system has to carry away the residual heat. The residual heat load is about 3% of the heat load under normal operating conditions.
The earthquake destroyed the external power supply of the nuclear reactor. That is one of the most serious accidents for a nuclear power plant, and accordingly, a “plant black out” receives a lot of attention when designing backup systems. The power is needed to keep the coolant pumps working. Since the power plant had been shut down, it cannot produce any electricity by itself any more.
Things were going well for an hour. One set of multiple sets of emergency Diesel power generators kicked in and provided the electricity that was needed. Then the Tsunami came, much bigger than people had expected when building the power plant (see above, factor 7). The tsunami took out all multiple sets of backup Diesel generators.
When designing a nuclear power plant, engineers follow a philosophy called “Defense of Depth”. That means that you first build everything to withstand the worst catastrophe you can imagine, and then design the plant in such a way that it can still handle one system failure (that you thought could never happen) after the other. A tsunami taking out all backup power in one swift strike is such a scenario. The last line of defense is putting everything into the third containment (see above), that will keep everything, whatever the mess, moderator rods in our out, core molten or not, inside the reactor.
http://anond.hatelabo.jp/20110314030613
へ続く
http://anond.hatelabo.jp/20090121125115
（M）どこを見回してもすべき仕事がある。
（A）あらゆるところに、なすべき仕事がある。
（Y）なすべき仕事は至る所にある。
（M）経済状況は、大胆で迅速な行動を求めている。我々は新しい職場の創造だけでなく、成長のため新しい基盤を作らねばならない。
（A）経済状況は、力強く迅速な行動を求めている。私たちは行動する。新たな雇用を創出するだけではなく、成長への新たな基盤を築くためにだ。
（Y）米国経済は、大胆かつ迅速な行動を求めている。そして我々は新規の雇用創出のみならず、新たな成長の礎を整えることができる。
（M）我々は道路や橋、電線やデジタル通信網をつくり、我々の商業を支え、我々の結びつきを強めなければならない。
（A）商業の糧となり、人々を結びつけるように、道路や橋、配電網やデジタル回線を築く。
（Y）道路や橋を造り、電線やデジタル通信網を敷き、商業を支え、我々を一つに結び付ける。
（M）我々は科学を本来あるべき場所に引き戻し、技術を活用し医療の質を引き上げると共にコストを下げる。
（A）科学を本来の姿に再建し、技術の驚異的な力を使って、医療の質を高め、コストを下げる。
（Y）科学を本来あるべき地位に戻し、医療の質を引き上げながら、そのコストは減らす。
（M）太陽、風や土壌を使って我々の自動車の燃料とし、工場を動かす。
（A）そして太陽や風、大地のエネルギーを利用し、車や工場の稼働に用いる。
（Y）太陽、風や土壌を利用して自動車を動かし、工場を動かす。
（M）我々の学校や単科大、大学を新たな時代の要請にあわせるようにする。
（Y）新時代の要請に合うよう学校や単科大、大学を変えていく。
（M）これらすべてが我々には可能だ。
（A）これらすべては可能だ。
（Y）我々はすべてのことを成し遂げられる
（M）これらすべてを我々は実行するのだ。
（A）そしてこれらすべてを、私たちは実行する
（Y）し、行っていく。
（M）我々の志の大きさに疑問をはさむ人もいる。
（A）私たちの志の大きさに疑念を抱く人がいる。
（Y）我々の野望の大きさについて疑念を抱く人がいる。
（M）我々のシステムでは大きすぎる計画は達成できないという人々だ。
（A）我々のシステムではそんなに多くの大きな計画は無理だ、と言うのだ。
（Y）我々のシステムは多くの大きな計画に耐えられないと指摘する人もいる。
（M）彼らは覚えていないのだ。
（A）だが、そうした人たちは忘れるのが早い。
（Y）だが、彼らは忘れている。
（M）彼らはすでにこの国が成し遂げたことを忘れているのだ。想像力が共通の目的に出会った時、必要が勇気と出会った時、自由な男女に達成できることを忘れているのだ。
（A）これまで我が国が成し遂げてきたこと、そして、共通の目的や勇気の必要性に想像力が及んだとき、自由な人々がどんなことを成し遂げられるかを、忘れているのだ。
（Y）彼らはこの国が何を成し遂げたかを忘れている。想像力が共通の目的と出合った時、必要が勇気と結びついた時、自由な男女が何を達成できるかを忘れているのだ。
（M）皮肉屋が理解できないのは、彼らの下で大地が動いたということだ。
（A）皮肉屋たちは、彼らの足元の地面が動いていることを知らない。
（Y）皮肉屋が理解できないのは、彼らがよって立つ地面が動いたということだ。
（M）我々を余りに長期間、消耗させた使い古しの政治論議はもはや適用されない。
（A）つまり、これまで私たちを消耗させてきた陳腐な政争はもはや当てはまらない。
（Y）長い間、我々を疲れさせてきた陳腐な政治議論はもはや通用しない。
（M）今日、我々が問うのは、政府が大きすぎるか小さすぎるかではなく、機能しているかどうかだ。
（A）私たちが今日問わなくてはならないことは、政府が大きすぎるか小さすぎるか、ではなく、それが機能するかどうかだ。
（Y）我々が今日問うべきなのは、政府の大小ではなく、政府が機能するか否かだ。
（M）家庭が人並みの収入を得られるよう仕事を見つけ、威厳をもって引退できるよう助けているかどうかだ。
（A）まっとうな賃金の仕事や、支払い可能な医療・福祉、尊厳をもった隠退生活を各家庭が見つけられるよう政府が支援するのかどうかだ。
（Y）家族が人並みの給与の仕事を見つけたり、負担できる（医療）保険や、立派な退職資金を手に入れることの助けに、政府がなるかどうかだ。
（A）答えがイエスならば、私たちは前に進もう。
（M）「ノー」の施策は廃止する。
（A）答えがノーならば、政策はそこで終わりだ。
（Y）ノーならば終わりとなる。
（M）公金を預かる我々は、説明責任を果たさなければならない。適切に支出し、悪い習慣を改め、誰からも見えるように業務を行う。
（A）私たち公金を扱う者は、賢明に支出し、悪弊を改め、外から見える形で仕事をするという、説明責任を求められる。
（Y）公的資金を管理する者は適切に支出し、悪弊を改め、誰からも見えるように業務を行う。
（M）それによって初めて、国民と政府の間の重要な信頼を回復できる。
（A）それによってようやく、政府と国民との不可欠な信頼関係を再建することができる。
（Y）それによって初めて、国民と政府の間に不可欠な信頼を回復できる。
（M）市場が正しいか悪いかも、我々にとっての問題ではない。
（A）市場が良い力なのか悪い力なのかも、問われていることではない。
（Y）問うべきなのは、市場の良しあしでもない。
（M）富を生み出し、自由を拡大する市場の力は比肩するものがない。
（A）富を生みだし、自由を広めるという市場の力は、比類なきものだ。
（Y）富を作り自由を広げる市場の力に比肩するものはない。
（M）だが、今回の金融危機は、注意深い監視がなされなければ、市場は制御不能になり、豊かな者のみを優遇する国は長く繁栄することはできないことを我々に気付かせた。
（A）しかし、今回の（経済）危機は、市場は注意深く見ていないと、制御不能になるおそれがあることを、私たちに思い起こさせた。また、富者を引き立てるだけでは、国は長く繁栄できない、ということも。
（Y）だが、今回の（経済）危機は、監視がなければ、市場は統制を失い、豊かな者ばかりを優遇する国の繁栄が長続きしないことを我々に気づかせた。
（M）我々の経済の成功は国内総生産の規模だけでなく、繁栄が享受される範囲や、望む人すべてに機会を広げる能力にかかってきた。
（A）私たちの経済的な成功は、国内総生産（ＧＤＰ）の規模だけではなく、繁栄がどこまで到達するかに常に依存してきた、つまり、意欲のある人にどれだけ機会を広げられたかだ。
（Y）我々の経済の成功はいつも、単に国内総生産（ＧＤＰ）の大きさだけでなく、我々の繁栄が広がる範囲や、機会を求めるすべての人に広げる能力によるものだった。
（M）慈善としてではなく、公共の利益に通じる最も確実な道としてだ。
（A）慈善心からではなく、それが、私たちの共通の利益への最も確実な道筋であるからだ。
（Y）慈善としてではなく、公共の利益に通じる最も確実な道としてだ。
KEREM SHALOM, Israel, July 11 ?? Real life has a way of intruding into the airy absolutes of the Israeli-Palestinian conflict. Each side may deny the other’s historical legitimacy, or plot the other’s demise, but somehow, the gritty business of coexistence marches on.
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Rina Castelnuovo for The New York Times
An Israeli man signaled for a truck to move toward Gaza at Sufa on Wednesday. Commerce continues despite the Hamas takeover.
The New York Times
For the past month, since the Islamic militants of Hamas took over the Gaza Strip, Israel has kept the main commercial crossing point at Karni shuttered, squeezing the life out of the limp Gazan economy. Israel bans contact with Hamas, and Hamas seeks Israel’s destruction, making border crossing etiquette more precarious than elsewhere.
Yet at this small crossing near the Egyptian border on Wednesday, between mortar attacks by Hamas and other militants, about 20 truckloads of milk products, meat, medicines and eggs passed from Israel into Gaza, part of the effort to keep basic commodities reaching the 1.5 million Palestinians of the largely isolated strip. Most of the supplies are not humanitarian relief, but are ordered by Palestinian merchants from Israeli suppliers, relying on contacts built up over years.
The mechanics of the crossover manage to answer Israel’s security needs while avoiding contact with Hamas. At Kerem Shalom, Israeli trucks transfer their goods to what Israeli military officials describe as a “sterile” Palestinian truck. Driven by a carefully vetted Palestinian driver, the truck never leaves the terminal, carrying the goods to the Palestinian side, where they are transferred onto ordinary Palestinian trucks that drive into Gaza.
Kerem Shalom, which means “vineyard of peace,” is surrounded by fences and concrete barriers. It can process only about 20 trucks a day, so it is reserved for products that require refrigeration.
The hardier goods, which make up the bulk of the supplies, go through another crossing, at Sufa, to the north. About 100 Israeli trucks a day come from Israel, swirling up clouds of dust before dumping thousands of tons of dry products, bales of straw and crates of fruit on “the platform,” a fenced-in patch of baked earth. At 3 p.m. the Israeli suppliers leave. Like drug dealers picking up a “drop,” the Gaza merchants send in trucks from a gate on the other side and take the products away.
Other products make their way into Gaza with virtually no human interaction. At the fuel depot at Nahal Oz, Israeli tankers pour diesel, gasoline and cooking gas into Gaza through pipes that run beneath the border. And even at Karni, the main crossing that closed for normal operations on June 12, the Israelis have adapted a 650-foot-long conveyor belt, which was previously used for gravel, to send in grain.
“It is better all around from a security point of view that commodities go in,” said Maj. Peter Lerner of the Coordination and Liaison Administration, the Israeli military agency that deals with the civilian aspects of the Gaza border. “More despair doesn’t serve anyone.”
Israeli officials cite security reasons for having shut Karni, the only crossing equipped to send containers into Gaza, or to handle exports out of the strip. “Karni was based on the concept of two sides operating together,” said Col. Nir Press, the head of the coordination agency.
Colonel Press noted that in April 2006, a vehicle loaded with half a ton of explosives got through three of four checkpoints on the Palestinian side of Karni, and was stopped at the last security position by members of the American-backed Presidential Guard, loyal to the Palestinian president, Mahmoud Abbas of Fatah.
But the Presidential Guard is no longer there, having been routed, along with all other Fatah forces in Gaza, by Hamas.
Instead, the military wing of Hamas and other Palestinian factions have been firing mortar shells at Kerem Shalom. On Tuesday, 10 of them landed in and around the terminal as two trucks of milk were passing. The crossing was closed for the rest of the day. [Another barrage of mortar shells hit areas around Kerem Shalom on Thursday.]
Hamas suspects that Israel wants to use Kerem Shalom to replace the Rafah crossing on the Egypt-Gaza border, which has been closed since June 9. The Palestinians had symbolic control at Rafah. At Kerem Shalom, Israel can better supervise who ?? and what ?? is going in and out of the strip.
“Kerem Shalom is a military post, a place from which Israeli tanks begin their incursions into Gaza,” said Fawzi Barhoum, a Hamas spokesman, justifying the mortar attacks. “How can we consider it a safe and legitimate crossing to replace Rafah?”
But when it comes to food, rather than principle, Hamas is proving itself pragmatic as well. On Sunday, Palestinian merchants, trying to press Israel to reopen Karni, told the Israelis that Hamas had barred the import of Israeli fruit. But by Wednesday, the Israeli fruit was ordered again. “Hamas does not want to lose the private sector,” a Gaza businessman explained.
Tellingly, the exposed Sufa crossing, through which most of the food comes, has not been attacked with mortars so far. Without Karni, however, and with the smaller crossings operating on a one-way basis, Gaza can barely subsist. With hardly any raw materials going in, and no products from Gazan farms, greenhouses and factories so far allowed out, Gaza’s tiny industrial base is on the verge of collapse.
Hamas officials say they want to start negotiations with Israel about reopening the formal crossings. Major Lerner said that Hamas had “a few things to do” first, including recognizing Israel’s right to exist and freeing Gilad Shalit, the Israeli soldier captured and taken to Gaza in a raid more than a year ago.
But the ultimate test of pragmatism may come in September when the Hebrew calendar enters what is known in Jewish law as a “shmita” year. Then the fields of Israel are supposed to lie fallow, and observant Jews seek agricultural products grown elsewhere. Before the Hamas takeover, Israel’s rabbis had reached agreements with Palestinians to import vegetables from Gaza, Major Lerner said. Given the needs of both sides, it may still happen.
